Bengaluru: On 20 July, 1969, Apollo 11 astronauts Neil Armstrong and Edwin ‘Buzz’ Aldrin landed on the Moon in what was one of humanity’s greatest leaps of progress in science. The process leading up to the mission was neither simple nor easy. As with every complex space mission, not everything went as planned.
On the 50th anniversary of Apollo 11’s Moon landing, ThePrint takes you through how the actual landing happened and what the two astronauts did on the lunar surface.
After the spacecraft reached the lunar orbit, Apollo 11 had made 10 revolutions of the Moon before it was time for Armstrong and Aldrin to venture on to the lunar surface. The command ship of this mission was called Columbia and it was to remain in orbit around the Moon with pilot Michael Collins, while the lunar module (LM) called ‘Eagle’ – which is the lander spacecraft – was to touch down with the two astronauts. The two were connected by a tube.
The Eagle could use its ‘descent stage’ to lower itself on to the Moon and again utilise the ‘ascent stage’ to launch and dock back with Columbia.
Just before the two astronauts entered LM, the panic alarm had gone off. The mission control team identified it as a computer overload. The crew was instructed to ignore the alarm and proceed.
Once aboard the LM, Armstrong and Aldrin detached from Columbia – now occupied solely by Collins. As the LM floated away from orbit, Collins had remarked: “Eagle has wings.”
‘Towards Mare Tranquillitatis’
The LM was initially on autopilot and performed a curved trajectory around the Moon before navigating towards the landing spot. During the process, there was a communication blackout for nearly an hour when the LM travelled on the other side of the Moon even as lunar thrusters were fired to slow it down.
When the LM slowed down and was finally steered to its designated landing site by an automated guidance computer, there was a sudden realisation that the vehicle was attempting to land on a crater filled with boulders. It was later established that there had been an error in data supplied to the automated guidance system.
Armstrong had to quickly take manual control of the vehicle and steer it in a different direction for a safe landing.
At the time, Collins’ instructions were to fly back to Earth in case Armstrong and Aldrin were unable to launch from the lunar surface onto the command ship. This almost seemed like a possibility since Armstrong’s manoeuvring had also burnt extra fuel that was needed to go back to Earth.
The spot on which they finally landed on 20 July, 1969, 20:17 UTC was 6.5 kilometres to the west of the initial landing site, in what is known as Mare Tranquilis or the Sea of Tranquility.
The successful message that Armstrong relayed went like this: “Houston, Tranquility Base here. The Eagle has landed.”
Nearly six and a half hours of rest later, Armstrong prepared for his moon walk. He ran into immense difficulty while trying to squeeze out of the hatch door while wearing his white portable life-support suit. The astronauts’ suits measured all their vitals and both Armstrong and Aldrin had the highest heart rates moments before they were to step on the Moon.
Once he was able to get on to the ‘porch’, Armstrong announced his status and started his descend on the lunar surface using a ladder. He released a camera that was able to capture humanity’s very first footstep on the Moon.
“That is one small step for a man, one giant leap for mankind,” Armstrong had remarked famously on 21 July 1969, 02:56 UTC. This quote has been immortalised through the decades without the crucial “a” in it.
Also read: Human history on the moon needs protection, 50 years after Armstrong left his footprints
On the lunar regolith
The site of landing measured temperatures of approximately -17 degrees Celsius. As soon as Armstrong stepped on the surface, he collected a sample of lunar soil, called regolith, and kept it inside his pocket – in case an emergency prevented the astronauts from staying there further.
Armstrong then used a camera to capture a panoramic view of the surface before mounting it on a tripod and welcoming Aldrin on to the surface. Buzz Aldrin’s first words “magnificent desolation” captured the landscape perfectly.
Armstrong and Aldrin were at ease with the lunar gravity, stating they had “no trouble at all”. But they needed to plan their steps in advance before attempting to walk. They also tried a variety of jumps, including a “kangaroo hop”.
After planting the American flag and speaking to the then US President Richard Nixon, the duo proceeded to begin their scientific activities.
They first planted seismic instruments to measure moonquakes and retroreflectors which reflect lasers from and back to Earth. These are used to accurately measure the distance of the Moon from the Earth.
NASA is sending yet another reflector on Chandrayaan-2, scheduled to be launched Monday.
Armstrong then moved around taking pictures while Aldrin collected soil and rock samples. They had 34 minutes on the Moon and intended to document all their processes. But they realised that their activities were taking more time than expected and had to turn off the camera. As Armstrong jumped from task to task, his body heated up rapidly and he was asked to slow down.
Despite this, their body vitals were normal and the two astronauts were granted a 15 minute extension on the Moon’s surface.
Collins, in the meanwhile, was orbiting around the Moon.
When Columbia went on the far side of the Moon for the first time after the Eagle detached, Collins had said that he felt an “awareness, anticipation, satisfaction, confidence and almost an exultation.”
When it was finally time to return to the LM, Aldrin first entered the Eagle and prepared to collect the 22 kilograms of lunar samples and filming equipment that Armstrong would give him. They left behind several items in memory of the crew of Apollo 1 – astronauts Roger Chaffee, Gus Grissom, and Edward White – who died in a test flight fire, in memory of Soviet cosmonauts Yuri Gagarin and Vladimir Komarov, symbols and messages of peace, a plaque of NASA management and messages of goodwill from international world leaders.
After seven hours of sleep on the LM, Armstrong and Aldrin finally prepared to attach with Columbia again.
Atmosphere: Earth’s last barrier
Columbia consisted of the command module – which housed the astronauts – and the service module – which provided oxygen, power and water. Before its re-entry, the service module was supposed to detach from Columbia, manoeuvre away from the command module’s re-entry path and burn up in the atmosphere.
But the service module detached and simply re-entered along with the command module. Fortunately, nothing went wrong and the crew was able to crash land in the ocean.
Spacecraft usually land in water for a multitude of reasons. Water acts as a cushion and its buoyancy simulates low gravity, giving returning astronauts a transition for Earth’s gravity. Also, a near-uniform ‘colour’ of the ocean and the astronauts, who are dressed in orange-coloured suits, also mean they can be easily spotted.
What engineers, who had programmed the ocean landing, could not account for was the weather. A huge storm was brewing above the Pacific Ocean, right at the spot where the vehicle was to crash. So, the crew was instructed to divert 400 kilometres away from their original spot of landing.
As a result they were away from any recovery ship or help and no footage of them returning to Earth was possible.
Once they were rescued, the crew was immediately quarantined to prevent any potential, even if unlikely, contamination. They were kept in isolation for three weeks in three different locations before being declared safe.
On the day of landing, just like any other traveler entering the country, the astronauts had to pass through customs at Hawaii airport. They had declared carried Moon rocks, Moon dust and soil samples at the customs.
Also read: As India prepares for another Moon mission, here is what makes Chandrayaan-2 special
Thanks. The article is a day late but better late than never. Time for humans to go back to the moon.